Build your gacha on FLETCHER

You are building an integration on FLETCHER (fletcher.cards), a real-asset graded-card gacha platform. Physical PSA/CGC/BGS slabs sit in insured custody; each is mirrored 1:1 as a MirrorCard ERC-721 on Robinhood Chain. Users rip gacha packs, trade, sell back, and redeem physical cards. You will build against FLETCHER's public worker API and on-chain contracts. No API key exists; do not invent one.

CONSTANTS
- Chain: Robinhood Chain, chainId 4663 (EVM). Explorer: https://robinhoodchain.blockscout.com
- Settlement token: USDG, ERC-20 at 0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168, 6 decimals. All amounts on the wire are 6-decimal base units as decimal STRINGS.
- Worker API base: https://fletcher-worker.onrender.com
- Contract discovery: GET /config returns { intake, mirror, mover, treasury, usdg, chainId, vaultRecipient }. Resolve addresses at runtime; never hardcode anything except USDG.

FIRST ACTIONS (do these before writing integration code)
1. GET /machines — the live gacha catalog: slug, name, category, priceUsd, evUsd, odds, stock, buybackPct, noTurbo, noBuyback.
2. GET /config — contract addresses and vaultRecipient.
3. GET /agents.md — the full, always-current API reference as raw markdown. Read it; it supersedes anything stale here.

CORE INVARIANT
Every paid rip terminates in exactly one of two states: a MirrorCard minted to the buyer, or a full refund of the deposit. There is no third state. A stuck flow self-heals server-side.

THE MONEY RAIL (every paid flow follows these five steps)
1. Health gate: GET /health must return 2xx before any wallet interaction.
2. Generate a sagaId: 32 cryptographically random bytes, 0x-hex (bytes32). It is BOTH the on-chain deposit tag and the worker's job key. Fresh per attempt; on-chain reuse reverts.
3. Arm the worker FIRST: POST the intent (e.g. POST /rip) BEFORE moving money so the deposit watcher is armed.
4. Approve + deposit: check USDG allowance(user, intake); approve if short (infinite approval is normal); after the approve receipt RE-POLL allowance before depositing (stale RPC nodes cause spurious reverts). Then call Intake.deposit(sagaId, amount) — ABI: deposit(bytes32,uint256); payer(bytes32) view returns (address).
5. Poll to terminal every 2-5 s. Rip terminal states: completed (card minted; mirror.tokenId + txHash), auto_sold (turbo Common paid out as USDG), refunded. A poll timeout is NOT failure — the saga completes server-side; re-hydrate from GET /rips/<wallet>.

DEPOSIT MATH (6-decimal base units)
- Rip / CC-marketplace buy / offer / gift: ccBase = round(priceUsd * 1e6); buffer = 250000 + ccBase/1000; deposit = ccBase + buffer (+ referral fee if attached). The buffer covers the bridge hop to Solana where the physical card settles.
- Member-marketplace buy / redemption: deposit the EXACT quoted amount. No buffer. Adding one overcharges the user.
- Referral (optional partner revenue): register a handle via POST /referral {handle, wallet}; then on each rip add referrer + referralFeeUsdc = ccBase/100 (1%) to the body and add that 1% to the deposit. It pays the referrer wallet automatically after the rip.

KEY ENDPOINTS
- Rip: POST /rip { id: sagaId, user:{base}, machineSlug, pricePaidUsdc, gachaCostUsdc, vaultRecipient, turbo } then poll GET /rip/<id>. turbo:true auto-sells a Common pull for instant USDG.
- CC-marketplace buy: same POST /rip with machineSlug:"" and a listing:{nftAddress, priceUsd, currency, tokenStandard, sellerWallet, card} object.
- Member marketplace: GET /member-listings; buy via POST /member-buy { id, buyer:{base}, seller:{base}, cardMint, mirrorTokenId, priceUsdc } + exact deposit, poll GET /member-buy/<id>. List: POST /list (signed). Delist: POST /delist (signed).
- Offers on CC cards: POST /offer { id, user:{base}, cardMint, ccCardId, priceUsd, offerUsdc, sellerWallet, card } + deposit(bid+buffer); placement is terminal at state "open" (1-2 min); the FILL can take days — track GET /offers-mine/<addr>; cancel via signed POST /offer-cancel.
- Instant sell (within 72h of the RIP): GET /sell-quote/<mint>, then signed POST /sell at EXACTLY the quoted amount, poll GET /sell/<id>. Requires one-time ERC-721 setApprovalForAll(user -> mover address from /config).
- Gifts: POST /gift/create (rip-style deposit; returns a bearer claim token — treat the link as money), POST /gift/claim, POST /gift/open, GET /gift/<token>, GET /gifts/<wallet>.
- Battles: GET /battles, GET /battle/<id>; POST /battle/create (signed), POST /battle/join (signed) then deposit EXACTLY the returned depositUsdc; seat holds 10 min; retrying a rejected payment reuses the SAME sagaId (the one sanctioned reuse).
- Physical redemption: POST /redeem-quote {insuredUsd, country}; POST /redeem (signed, shipping details); deposit the WORKER's returned quote exactly; poll POST /redeem-status (signed).
- Inventory & card data: GET /rips/<addr> (durable inventory), GET /card-by-token/<tokenId>, GET /value/<tokenId>, GET /card/<mint>, GET /meta/<tokenId>, GET /holders, GET /recent-openings.
- Social (optional): GET /feed, /posts/<wallet>, /post/<id>, /profile/<addr-or-@handle>, /notifications; writes POST /post, /post/like, /post/delete, /follow, /unfollow. Realtime: wss://fletcher-worker.onrender.com/ws (read-only; types chat, bchat, pull).

AUTH MODELS
- Reads: public, no auth.
- POST /rip, /member-buy, /offer, /gift/create: NO signature — the tagged on-chain deposit IS the authorization.
- Signed endpoints use EIP-191 personal_sign over byte-exact templates, ts = ms epoch within +/-10 min. Templates (copy exactly; prefixes are historical): "SCALPERS: list <cardMint> for <priceUsd> USDC ts <ts>", "SCALPERS: delist <cardMint> ts <ts>", "SCALPERS: sell <cardMint> saga <id> ts <ts>", "SCALPERS: cancel-offer <cardMint> saga <id> ts <ts>", "FLETCHER: redeem <cardMint> saga <sagaId> ts <ts>", "FLETCHER: battle-create <machineSlug> x<seatsTotal> ts <ts>", "FLETCHER: battle-join <battleId> saga <sagaId> ts <ts>", "FLETCHER: post <keccak256-hex-of-text> ts <ts>", "FLETCHER: social like|follow|unfollow|delete <target> ts <ts>", "FLETCHER: notifications <wallet> ts <ts>".

HARD RULES (violating these loses user money or double-charges)
1. Buffered vs exact deposits: rips/CC-buys/offers/gifts add the buffer; member-buys/redemptions are exact. Never mix these up.
2. Order matters: health gate -> POST intent -> approve -> deposit -> poll.
3. Fresh sagaId per money attempt (except battle payment retry).
4. Initiate payment only from an explicit user gesture, never from a render effect (React StrictMode double-fires effects and will double-charge).
5. Never retry a user-rejected wallet action. Retry stale-node simulation reverts up to 3x.
6. Fetch the live price at pay time and abort if it exceeds the displayed price.
7. Quotes (sell, redeem) are live and must be used exactly; never cache or recompute them.
8. Amounts are strings in JSON. Convert with round(dollars * 1e6).
9. The 72h buyback window runs from RIP time.
10. Poll at 2-5 s, not tighter; catalog endpoints are server-cached.

Support: https://t.me/fletchercards (include the sagaId in any money question). CORS: server-side calls need nothing; for browser calls from a new domain, ask FLETCHER to allowlist the origin.

Start by fetching /machines, /config, and /agents.md, then confirm your integration plan with the developer before writing money-path code.